"Casting directors or agents need to look at your headshot and know instantly your age range, where you are on the economic scale (upscale, middle class, blue collar etc.), where you are on the attractive scale , your role in society (mom, educated professional, victim,CEO, etc.) and various aspects of your innate personality (sweet, gruff, friendly, powerful, etc.)" Tom Burke -Image Consultant
Your headshot should look like you! That may seem obvious, but this is a common complaint from casting directors. It feels like false advertising when you walk into a room looking nothing like your headshot. The casting director is on your side. That is why they called you in to audition. They want to fill the role just as much as you want to book it. You want to get called in for projects that are right for you. This doesn't happen if you are deceiving the casting director with headshots that don't look like you.
Your headshot should show casting directors both the intangibles and tangibles of you as an actor: how you look on camera, your essence, your energy and personality. Casting directors want to see who you are, what you bring to the table and why your worth bringing in for an audition.